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STATE  OF  ILLINOIS 
DEPARTMENT  OF  REGISTRATION  AND  EDUCATION 

A.  M.  SHELTON,  Director 

DIVISION  OF   THE 

STATE  GEOLOGICAL  SURVEY 

M.  M.   LEIGHTON,  Chief 
REPORT  OF  INVESTIGATIONS-NO.  6 

PROPER  TESTING  FOR  OIL  STRUCTURES  IN  ILLINOIS 

AND  SOME  AREAS  DESERVING 

SUCH  TESTING 

BY 
GAIL  F.   MOULTON 


PRINTED  BY  AUTHORITY  OF  THE  STATE  OF  ILLINOIS 


URBANA,  ILLINOIS 
1925 


STATE  OF  ILLINOIS 
DEPARTMENT  OF  REGISTRATION  AND  EDUCATION 

DIVISION  OF  THE 
STATE  GEOLOGICAL  SURVEY 

M.  M.  LEIGHTON.  Chief 


Committee  of  the  Board  of  Natural  Resources 
and  Conservation 

A.  M.  Shklton,  Chairman 

Director   of   Registration   and    Education 

Kendric  C.  Babcock 

Representing   the   President   of  the   Uni 
versity  of  Illinois 

Edsox  S.  Bastin 
Geologist 


Schnepp  &  Barnes,  Printers 

Springfield,  III. 

1925 

34638 — 3000 


PROPER  TESTING  FOR  OIL  STRUCTURES  IN  ILLINOIS  AND 

SOME  AREAS  DESERVING  SUCH  TESTING 

By  Gail   F.  Moulton 

OUTLINE  page 

Proper  testing  tor  oil  structures 5 

Introduction     5 

Test  drilling  for  structure 5 

Relation  of  oil  accumulation  to  geologic  structure 5 

Determination   of  structure 6 

Field  conditions  in  Illinois 6 

The  use  of  key  beds  and  structure  tests 6 

Geological  data  already  available 6 

The  expense  of  haphazard  drilling 7 

Survey  cooperation  in  test  drilling 9 

Some  areas  deserving  oil  structure  testing 9 

Introduction     9 

Favorable  areas  in  western  Illinois 9 

Fulton   County    9 

Canton   anticline    11 

Babylon    anticline    11 

Fulton   and   Warren    counties 13 

The  Avon   area 13 

Henderson,  McDonough  and  Warren  counties 14 

Sciota-Good   Hope  area . 14 

Favorable  areas  in  central  Illinois 16 

Bond   County    16 

Stubblefield  anticline   16 

Montgomtry  County    18 

Nokomis   and  Ohlman   domes 18 

Favorable  areas  in  southern  Illinois 20 

St.  Clair  and  Washington  counties 20 

Darmstadt  area    20 

General   summary    22 

figure  ILLUSTRATIONS  page 

1.  Diagrams  of  relations  of  oil  and  gas  accumulation  to  folding  and  faulting  4 

2.  Index  map  showing  location  of  areas  described  in  the  report 8 

3.  Structure  map  and  generalized  columnar  section  of  area  near  Canton  in 

Fulton   County    10 

4.  Structure  map  and  generalized   columnar  section  of  area  near  Babylon 

in  Fulton  County   12 

5.  Structure  map  and  generalized  columnar  section  of  Avon  area  in  Fulton, 

Knox,   and   Warren   counties 13 

6.  Structure  map  and  generalized  columnar  section  of  area  near  Good  Hope 

in   McDonough   County 15 

7.  Structure  map  and   generalized   columnar  section  of  area  near   Stubble- 

field  in  Bond  County 17 

8.  Structure  map  and  generalized  columnar  section  of  Nokomis-Ohlman  area 

in  Montgomery  County 19 

9.  Structure  map  and  generalized  columnar  section  of  Darmstadt  area  in  St. 

Clair  and  Washington   counties 21 

TABLE 

1.     Comparative  costs  of  development  methods 7 


Pig.  1.  Diagrammatic  cross-sections  showing  effect  of  geologic  structure  on 
oil  accumulation.  In  B  the  fault  plane  is  supposed  to  afford  a  channel  by  which 
the  oil  has  escaped,  whereas  in  C  and  D  the  structure  forms  an  effective  trap. 


TROPER  TESTING   FOR  OIL  STRUCTURES   IN    ILLINOIS  O 

PROPER  TESTING  FOR  OIL  STRUCTURES 

Introduction 

Studies  by  the  oil  and  gas  section  of  the  State  Geological  Survey  re- 
veal a  number  of  localities  in  Illinois  which  appear  to  have  structures  worth 
testing  for  oil.  Few  of  these  are  definitely  outlined,  but  many  good  loca- 
tions are  likely  to  be  found  by  drilling  a  few  wells  to  a  shallow  key  horizon. 
It  is  the  purpose  of  this  report  to  outline  the  most  satisfactory  method  of 
exploring  for  oil  in  Illinois  and  to  call  attention  to  some  of  the  areas  which 
are  worthy  of  testing.     Other  areas  will  be  described  in  later  reports. 

Test  Drilling  for  Structure 

Test  drilling  as  considered  here,  includes  all  drill  holes,  both  diamond 
and  churn  drilled,  which  are  carried  down  to  some  shallow  bed  that  can  be 
recognized  easily  over  considerable  areas.  Generally  limestones  and  coal 
beds  have  been  used  as  key  beds,  because  they  are  easily  recognized  by  the 
driller  and  are  usually  logged.  Data  from  a  number  of  such  tests  can  be 
used  to  determine  the  amount  and  direction  of  dip  or  slope  of  the  beds  of 
underlying  rocks.  Because  in  most  parts  of  the  State  the  rocks  at  consider- 
able depth  have  a  structure  similar  to  that  of  the  rocks  near  the  surface, 
especially  in  local  features,  the  determination  of  the  structure  of  shallow 
key  beds  helps  to  determine  the  structure  of  deeper  rocks  which  might  con- 
tain oil  or  gas. 

The  Relation  of  Oil  Accumulation  to  Geologic  Structures 

The  oil  pools  which  have  been  found  in  Illinois  occur  chiefly  along  the 
high  parts  of  domes  and  anticlines.  A  similar  relation  between  rock  struc- 
ture and  oil  accumulation  has  been  observed  in  many  other  fields.  The 
general  relations  are  indicated  in  figure  1,  in  which  A  illustrates  the  typical 
case  of  an  unfaulted  area;  B  shows  a  fault  permitting  the  escape  of  oil  and 
gas  ;  C  and  D  show  faults  which  assist  in  causing  oil  accumulation.  Lately, 
such  fault  structures  causing  accumulation  are  known  as  the  "Mexia" 
(  Ale-He-a )  type. 

Knowledge  of  the  relation  of  oil  accumulation  to  structural  features  has 
resulted  in  a  program  of  locating  oil  tests  on  anticlines  and  domes.  Con- 
siderable success  in  finding  new  oil  pools  has  followed.  In  view  of  the  fact 
that  the  risks  of  oil  prospecting  are  considerably  reduced  by  drilling  on 
promising  structures,  favorable  structural  features  should  be  found  before 
drilling  for  oil  and  gas. 


<»  proper  testing  for  oil  structures  in  illinois 

Determination  of  Structure 

field  conditions  in  illinois 
In  many  regions  outside  Illinois,  the  rock  strata  outcrop  and  the  geo- 
logic structure  can  be  determined  by  the  correlation  of  key  beds  from  sur- 
face observations.  In  Illinois,  however,  the  thick  cover  of  glacial  deposits 
generally  conceals  the  consolidated  rocks  so  that  in  most  parts  of  the  State 
it  is  necessary  to  depend  on  subsurface  data  from  wells  for  determining  the 
structure.  Figure  1  shows  how  a  cover  of  glacial  drift  obscures  the  struc- 
ture of  the  bed  rock  below,  and  also  shows  the  lack  of  significant  relation 
between  topography  and  structure  of  the  underlying  rocks  in  a  glaciated 
region.  For  example,  in  figure  1  B  there  is  a  considerable  hill  which  over- 
lies a  structural  depression  or  syncline  in  the  right  side  of  the  diagram.  A 
valley  is  also  shown  over  part  of  an  anticline  in  figure  1  A.  This  situation 
is  typical  for  most  of  Illinois,  and  so  the  "lay"  of  the  land  is  not  dependable 
in  determining  the  oil  possibilities. 

THE  L'SE  OF  KEY  BEDS  AND  STRUCTURE  TESTS 

In  figure  1,  a  coal  bed  is  shown  which  would  be  suitable  for  use  as  a 
key  horizon  in  structural  determinations.  Test  wells  would  give  the  depth 
of  this  bed  at  different  points.  Then,  by  subtracting  the  depth  of  the  bed 
from  the  altitude  of  the  top  of  each  well,  altitudes  for  various  points  on  the 
surface  of  the  key  bed  could  be  obtained  to  determine  the  structure.  Ob- 
viously, accurate  determinations  of  both  the  depth  of  the  bed  and  the  ele- 
vation of  the  well  are  required  for  accurate  results.  Careful  and  complete 
records  of  the  wells  are  also  essential  for  accurate  identification  of  the  key 
beds  used. 

GEOLOGICAL    DATA    ALREADY    AVAILABLE 

Thousands  of  coal  tests  and  oil  wells  have  been  drilled  in  Illinois,  and 
as  a  result  of  the  efforts  of  the  Illinois  State  Geological  Survey,  numerous 
records  have  been  collected  and  studied.  Structure  maps  for  various  parts  of 
the  State  that  have  been  prepared  from  these  records  have  been  published  in 
connection  with  quadrangle  studies,  and  coal  and  oil  investigations.  An 
oil  and  gas  map  of  the  State1  showing  the  known  structures,  both  producing 
and  nonproducing,  has  been  compiled  from  the  more  detailed  maps.  In 
a  few  cases  the  domes  indicated  were  definitely  outlined  by  the  information 
available  from  shallow  tests.  Some  such  structures  have  since  produced 
oil  or  gas. 

More  commonly  the  data  have  been  sufficient  to  indicate  only  the  pres- 
ence of  an  irregularity  in  dip  which  might  be  due  to  a  real  doming,  but  for 

'Oil   and   gas   field    map   of    Illinois;   by   IT.   S.   Geological   Survey   and    Illinois   State 
Geological   Survey  in  cooperation,  1921. 


PROTER  TESTING   FOR  OIL  STRUCTURES   IN    ILLINOIS 


which  neither  the  form  nor  the  highest  point  are  known.  In  many  such 
cases  a  lew  test  wells  to  a  shallow  depth  would  give  the  data  necessary  for 
a  definite  determination  of  structural  conditions.  Areas  of  this  kind  have 
been  described  near  Decatur  and  Taylorville.2 

The  Expense  of  Haphazard  Drilling 

The  drilling  of  deep  tests  without  first  attempting  to  determine  the 
structure  is  both  expensive  and  unjustified.  A  consideration  of  the  relative 
costs  of  test  drilling"  and  drilling  to  depth  for  oil  emphasizes  the  saving  to 
be  made  by  drilling  test  wells  first.  Recent  drilling  near  Decatur  seems 
to  be  rather  typical  of  the  development  that  is  carried  out  generally  in  the 
State.  Here  the  value  of  shallow  tests  was  ignored,  and  several  deep  tests 
were  drilled.  The  estimated  cost  relations  are  indicated  in  the  accompany- 
ing table. 


Table  1.     Comparative  cost  of  development  methods. 

Plan  used  at  Decatur 

Cost 

Good  test  drilling  program 

Cost 

5  deep  tests    (2000  feet)    at 
average  of  $7500  each 

$37,500 

10  tests  to  coal   (400  feet)   at 
$1000  each 
2  deep   tests    (2000   feet)    at 
$7500  each 

Total 

$10,000 

Total 

$37,500 

15,000 

$25,000 

According  to  these  figures,  test  drilling  would  have  resulted  in  the  saving 
of  $12,500  or  33  per  cent  of  the  approximate  cost  of  the  drilling  at  Decatur. 
In  addition  there  are  other  advantages  in  the  test  drilling"  plan.  At  the 
present  time  the  deep  wells  drilled  at  Decatur  have  not  shown  whether  a 
closed  dome  of  commercial  promise  exists  there  or  not.  In  fact,  the  best 
location  may  be  untested.  A  series  of  shallow  tests  followed  by  drilling 
of  two  deep  tests  would  have  determined  the  size,  form  and  location  of  the 
structural  features  in  the  area,  and,  if  significant,  would  have  insured  test- 
ing of  the  most  favorable  parts  of  the  area.  Further,  a  few  indiscriminate 
deep  holes  may  give  an  area  a  bad  reputation,  whereas  methodical,  inexpen- 
sive tests  to  key  horizons  may  later  show  it  to  be  a  possible  producing"  area 
if  drilled  in  the  proper  location.  The  drilling  of  shallow  structure  tests 
before  putting  down  deep  tests  is  effective  insurance  against  premature  and 
undeserved  bad  reputations. 

The  situation  at  Decatur,  which  is  neither  better  nor  worse  than  many 
others  in  the  State,  has  been  used  as  an  illustration  in  the  hope  that  Illinois 
prospectors  will  do  at  least  a  small  amount  of  preliminary  exploration  in 


2  Collingwood,    D.   M.,    Further   considerations   of   prospects   for   oil   in   the    Decatur 
area:  111.  State  Geol.  Survey,  Rept.  of  Investigations  No.   1,  1924. 


PROPER  TESTING   FOR   OIL  STRUCTURES    IN     ILLINOIS 


!•"!(..  2.    Index  map  showing  by  shading  the  location  of  areas 

described  in  the  report. 

1.  Good  Hope  ana.  .}.     NoUomis-Oblman  area 

2.  Avon  area.  6.    Stubblefield  area, 

3.  Babylon  area.  7.    Darmstadt  area. 
■I.    Canton  area. 


PROPER  TESTING   FOR   OIL  STRUCTURES   IN    ILLINOIS  9 

advance  of  deep  drilling.  In  many  localities  2  or  3  tests  to  a  depth  of  ap- 
proximately 200  feet  would  give  the  information  needed.  Test  drilling  of 
this  kind  should  have  a  definite  and  permanent  place  in  any  development 
program  in  a  wildcat  territory  of  the  Illinois  type. 

Survey  Cooperation  in  Test  Drilling 

The  Illinois  State  Geological  Survey  is  glad  to  cooperate  with  interested 
parties  by  giving  available  logs  of  wells,  drilling  depths,  and  other  helpful  in- 
formation. The  Survey  also  extends  its  best  service  to  operators  and  drillers 
in  identifying  the  various  rock  formations  encountered  and  in  sampling  the 
waters  of  the  various  horizons.  Well  record  books  and  convenient  equip- 
ment for  saving  well  cuttings  will  gladly  be  sent  without  charge  upon  re- 
quest. Conferences  in  regard  to  applying  the  above  structure-testing  plan 
are  invited. 

SOME  AREAS  DESERVING  OIL  STRUCTURE  TESTING 

Introduction 

Certain  areas  which  should  he  prospected  for  oil  by  the  method  of  test 
drilling  for  structure,  arc  described  in  the  following  pages.  Most  of  these 
have  been  described  in  previous  publications,  but  they  are  brought  to  the 
attention  of  drillers  in  the  hope  that  some  of  them  will  be  tested  during  the 
coming  year  and  found  to  be  of  commercial  promise.  The  areas  in  west- 
ern, central  and  southern  Illinois  recommended  for  prospecting  are  located 
on  the  index  map  (fig.  2). 

Favorable  Areas  in  Western  Illinois 

A  recent  investigation3  showed  that  testing  on  known  structures  in  a 
large  area  in  western  Illinois  resulted  in  finding  important  accumulations 
of  oil  or  gas  on  fifty  per  cent  of  the  structures.  At  the  present  time,  several 
structures  of  similar  character  are  known  to  be  untested. 

FULTON    COUNTY 

Two  areas  in  Fulton  County  which  seem  to  merit  further  testing  have 
been  indicated  on  the  Oil  and  Gas  Map  as  the  Canton  and  Babylon  anti- 
clines and  have  previously  been  described  in  a  bulletin  of  the  Geological 
Survey.4  The  accompanying  sketch  maps  (figs.  3  and  4)  are  taken  from  the 
report  on  the  area  and  show  the  form  and  locations  of  the  anticlines  in  a 

3  Collingwood,   D.   M.,   Oil   testing  in   Illinois:   111.  Acad,   of  Science  meeting  of   1923. 

4  Savage,    T.    E.,    Geology    and    mineral    resources    of    the    Axon    and    Canton    quad- 
rangles:  111.   State  Geol.   Survey  Bull.   38,  pp.   209-271,   1922. 


10 


PROPER  TESTING  FOR  OIL  STRUCTURES  IN    ILLINOIS 


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PROPER  TESTING   FOR  OIL  STRUCTURES   IN    ILLINOIS  11 

general  way,  because  the  tests  to  coals  have  not  been  distributed  widely 
enough  to  give  uniformly  detailed  structural  information.5 

THE   CANTON   ANTICLINE 

The  shaded  area  southwest  of  Canton  includes  the  highest  part  of  a 
plunging  anticline,  which  has  been  mapped  by  using  data  on  the  elevation 
of  a  persistent  coal  bed  reported  in  coal  tests,  and  found  in  outcrop  along 
some  of  the  streams.  The  coal  tests  and  outcrops  are  located  on  figure  3. 
Further  testing  on  the  north  and  west  sides  of  the  shaded  area  are  needed 
to  outline  the  structure  more  definitely. 

The  structure  tests  should  be  drilled  to  a  depth  of  about  100  feet  to 
reach  the  base  of  the  Springfield  coal.  The  outcrops  of  coal  along  the 
streams,  as  shown,  give  information  on  the  structure  in  the  eastern  part  of 
the  area,  so  the  structure  needs  to  be  determined  only  on  the  north  and  west 
sides.  Probably  three  or  four  tests  drilled  north  and  west  of  the  Toledo, 
Peoria  and  Western  Railroad  around  the  border  of  the  shaded  area  will 
show  whether  this  is  a  closed  structure. 

Three  possible  oil  horizons  should  be  tested  in  this  area  if  the  structure 
is  found  to  be  favorable.  These  are  the  Devonian  lime  at  about  800  feet, 
the  Hoing  sand  horizon  at  a  depth  of  about  900  feet,  and  the  Trenton  lime 
at  1100  to  1-100  feet.  The  top  of  the  St.  Peter  sandstone  will  probably  be 
reached  at  about  1400  feet.  (See  columnar  section,  fig.  3.)  Oil  tests  should 
not  be  drilled  below  this  horizon. 

THE  BABYLON  ANTICLINE 

The  Babylon  anticline  (fig.  4)  has  also  been  determined  from  the  com- 
bined use  of  drill  records  and  data  from  outcrops.  The  shaded  area  in- 
cludes the  part  of  the  fold  in  which  doming  seems  most  likely  to  be  found. 

Tests  for  structure  should  be  drilled  on  the  north  and  northwest  sides 
of  the  shaded  area  to  determine  whether  or  not  this  represents  a  closed 
structure.  The  key  horizon  nearest  the  surface  is  the  Colchester  coal. 
Tests  to  this  key  bed  would  be  about  50  feet  deep  over  most  of  the  area, 
but  care  should  be  taken  to  avoid  locating  a  test  where  the  coal  has  been 
removed  by  erosion.  Probably  three  tests  would  give  the  information 
necessary  to  determine  the  presence  of  a  dome. 

If  favorable  structure  is  found  in  this,  locality,  a  deep  test  should  be 
drilled  through  three  possible  oil  horizons.  These  are  the  Devonian  lime 
at  about  700  feet,  the  Hoing  sand  horizon  at  about  800  feet  and  the  Trenton 
lime  from  1000  to  1300  feet.  The  top  of  the  St.  Peter  should  be  reached 
at  about  1300  feet  and  marks  the  limit  of  known  oil  possibilities.  (See 
columnar  section,  figure  4.) 


5  Topographic  maps  of  these  areas  are  published  and  may  be  obtained  by  writing 
the  Chief,  Illinois  Geological  Survey,  Urbana,  for  maps  of  Canton  and  Avon  quad- 
rangles. Index  maps  showing  the  areas  which  have  been  surveyed  are  also  avail- 
able  upon   request. 


12 


PROPER  TESTING   FOR   OIL   STRUCTURES   IN    ILLINOIS 


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PROPER  TESTING   FOR   OIL  STRUCTURES    IN"    ILLINOIS 


13 


FULTON   AND  WARREN    COUNTIES 


THE   AVON    AREA 

The  Avon  area,  which  includes  parts  of  Fulton  and  Warren  counties, 
appears  to  have  structural  conditions  favorable  for  the  accumulation  of 
oil  or  gas.     The  structure  in  this  area  has  also  been  mapped  by  use  of  data 


R.1W. 


R.1E. 


'.'.ifvvi'&Oy     Pleistocene  system. 
I  Burlington 

J     limestone.     I  jfississippian 
I  Kinderhoek       "    system. 
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=  I  Devonian  system. 


Silurian  system. 


sand  horizon. 


Ordovieian 
system. 


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base  of 

test. 

crop 

of  Col- 

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chester 

favorable 

the  base  of 

lington 

Rook 

(No.  2) 

structure 

Colchester 

lime- 

Island 

coal. 

mav  be 

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stone. 

(No.  1) 
coal. 

found. 

coal. 

Fig.  5.    Structure  map  and  generalized  columnar  section  of  Avon  area  in  Fulton,  Knox, 

and  Warren  counties. 

from  drill  holes  and  outcrops  of  the  Colchester  coal.6  The  deep  tests 
shown  in  the  sketch  map  (fig.  5)  indicate  that  this  fold  is  more  pronounced 
in  the  deeper  beds  than  in  the  coal. 


6  Savage,    T.    E.,    Geology    and    mineral   resources    of   the    Avon    and    Canton    quad- 
rangles: 111.  State  Oeol.  Survey  Bull.  38,  pp.  209-271,  1922. 


1  I  PROPER  TESTING   FOR  OIL  STRUCTURES    IN    ILLINOIS 

In  order  to  complete  the  structural  determinations,  structure  tests  should 
be  drilled  across  the  north  and  in  the  central  part  of  the  shaded  area.  Such 
tests  would  determine  the  presence  of  possible  north  dip  and  the  location 
of  the  highest  part  of  the  structure.  Four  or  five  test  wells,  if  properly 
located,  would  give  the  information  needed. 

The  base  of  the  Burlington  limestone  is  the  best  key  available  in  this 
area.  It  should  be  found  at  a  depth  ranging  from  200  to  300  feet  accord- 
ing to  local  conditions.  This  drilling  should  be  inexpensive  because  little 
casing  will  be  required  and  the  lower  formations  should  not  cave  or  cause 
other  difficulties. 

In  case  favorable  structural  features  are  found,  the  beds  above  the  St. 
Peter  sandstone  should  be  tested  for  oil  and  gas.  The  possible  oil  horizons 
which  would  be  tested  by  such  drilling  are  the  Devonian  limestone  at  a  depth 
of  about  400  feet,  the  Hoing  sand  horizon  at  a  depth  of  about  500  feet,  and 
the  Trenton  lime  at  about  700  feet.  A  test  to  about  1050  feet  would  be  deep 
enough  to  constitute  a  thorough  test  on  the  higher  parts  of  the  fold.  (See 
columnar  section,  fig.  5.) 

HENDERSON,   MCDONOUGH,   AND   WARREN   COUNTIES 
SCIOTA-GOOD    HOPE  AREA 

Near  Sciota  in  northwestern  McDonough  County,  is  an  area  which 
seems  to  have  structural  conditions  favorable  for  oil  accumulation.  Figure 
6  is  taken  from  a  detailed  report  of  the  State  Geological  Survey  on  this 
general  area.7 

The  published  geologic  map  of  the  LaHarpe-Good  Hope  quadrangles 
indicates  the  presence  of  a  broad  general  arch  with  a  north-south  trend 
extending  from  the  vicinity  of  Stronghurst  in  sec.  25,  T.  9  N.,  R.  5  W., 
southeast  and  south  to  the  Colmar- Plymouth  fields  in  southwestern  McDon- 
ough County.  The  structure  of  the  area  has  been  determined  from  data  on 
the  elevation  of  the  base  of  the  Burlington  limestone.  Data  examined  in 
connection  with  the  present  report  indicate  that  the  shaded  area  shown  on 
the  map  is  probably  bounded  on  the  north  and  south  by  small  synclines. 

In  the  Sciota-Good  Hope  locality,  it  would  probably  be  advisable  to 
drill  the  first  test  near  the  center  of  the  shaded  area,  and  to  continue  test- 
ing both  north  and  south.  If  this  plan  is  followed,  the  first  test  might  show 
whether  marked  doming  has  taken  place  in  the  vicinity.  Tests  along  the 
north  and  south  borders  of  the  shaded  area  would  give  information  re- 
quired for  determining  the  size  and  shape  of  any  dome  which  might  be 
found.  Probably  six  tests  are  required  for  determining  the  structure  in 
this  area. 


7  Savage,  T.  E.,  and  Nebel,  M.  L.,  Geology  and  mineral  resources  of  the  LaHarpe- 
Good  Hope  quadrangles:  til.  State  Geol.  Survey  Bull.  43,  1021.  Topographic  maps 
are  available. 


PROPER  TESTING   FOR  OIL  STRUCTURES   IN    ILLINOIS 


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16  PROPER  TESTING   1-OR  OIL  STRUCTURES    IX    ILLINOIS 

The  base  of  the  Burlington  limestone  is  the  best  key  horizon  available 
here.  Over  most  of  the  shaded  area  it  should  be  found  at  depths  varying 
from  200  to  300  feet.  The  cost  of  tests  should  be  low  because  of  the  favor- 
able drilling  conditions. 

Three  possible  oil  producing  horizons  should  be  tested  in  the  area 
if  favorable  structural  conditions  are  found.  These  are  the  Devonian  lime 
at  about  500  feet,  the  Hoing  sand  horizon  at  about  600  feet,  and  the  Trenton 
lime  at  about  800  feet.  A  well  drilled  to  a  depth  of  1  100  feet  would  test  the 
possibilities  of  all  these  horizons.      (See  columnar  section,  fig.   li.  i 

Favorable  Areas  ix  Central  Illinois 

The  general  results  of  testing  domes  and  anticlines  in  central  Illinois 
have  been  satisfactory."  Nearly  half  of  the  domes  tested  have  yielded 
either  oil  or  gas.  In  this  area,  too,  several  promising  structures  are  known  to 
have  been  inadequately  tested.     Two  of  these  are  described  in  this  report. 

BO XI)    COUNTY 
STUBBLEFTELD   ANTICLINE 

The  Stubblefield  anticline  south  of  Greenville  has  produced  gas  for 
several  years.  More  recently  the  Ohio  Oil  Company  and  the  Bond  County 
<  ras  Company  have  drilled  a  few  small  gas  wells  on  the  Ayers  anticline 
north  of  Greenville.  Both  of  these  anticlines  have  been  shown  on  the  Oil 
and  ( ias  Map. 

A  recent  consideration  of  the  well  data  from  Bond  County  resulted 
in  the  structural  interpretation  shown  in  figure  ~, .  Abrupt  changes  in  the 
elevation  of  certain  beds  as  determined  from  well  logs  lead  to  the  con- 
clusion that  a  fault  crosses  the  Stubblefield  anticline  in  the  position  shown. 
The  vertical  displacement  of  this  fault  is  approximately  I"  feet.  As 
the  west  side  went  down  relative  to  the  east,  a  closed  structure  similar  to 
a  dome  is  produced  by  the  intersection  of  this  fault  and  the  Stubblefield 
anticline.  This  type  of  structure,  which  was  shown  in  figure  1,  has  pro- 
duced large  quantities  of  oil  in  Texas  and  smaller  amounts  in  many  other 
states. 

Test  drilling  to  determine  the  location  of  the  crest  of  the  anticline 
and  the  exact  trend  of  the  fault  should  precede  any  deep  drilling  for  oil. 
A  series  of  tests  scattered  along  the  highest  part  of  the  fold  should  ac- 
complish both  purposes.  Probably  5  tests  properly  located  would  provide 
the   desired   information. 


Collingwood,  D.   M.,  Oil  testing  in   Illinois:     III.   Acad,  of  Science  meeting  of  1923. 


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Illinois  State  Geological  Survey  Av.gust 

Urban a,  Illinois  1938 

Supplement  to  Report  of  Investigations  No.  6 
REVISED  DATA  OH  STUBBLEFIELD  ANTICLINE,  BOND  COUNTY,  ILLINOIS 

Instrumental  levels  of  wells  which  were  determined  since 
the  publication  of  Report  of  Investigations  No.  6  necessitate  re- 
vision of  the  structure  map,  figure  7,  page  17.   The  new  data, 
which  are  tabulated  below,  indicate  that  the  fault  shown  probably 
does  not  exist  and  no  closed  structures  are  indicated.   Doep  test- 
ing for  oil  is  not  recommended  unless  shallow  testing  to  coal  No.  6 
indicates  the  presence  of  closed  domes. 

Location  Surface  COS:  No.  6  E^eva~ 

Sec.  T.-N.  R.-W.   Company  and  well  elevation  Depth   tion 

(Foet)    (Feet)   (Feet) 


SE. 

SW. 

4 

5 

SW. 

NE. 

4 

5 

NE. 

NW. 

9 

5 

NE. 

NW. 

9 

5 

SE. 

SE. 

10 

5 

SE. 

SE. 

11 

5 

NW. 

NW. 

15 

5 

SW. 

NE. 

16 

5 

NW. 

NE. 

18 

5 

SW. 

SW. 

19 

5 

SE. 

SE. 

23 

5 

NW. 

SE. 

28 

5 

N.'.V 

.cor 

.30 

5 

NW. 

NE. 

32 

5 

se.: 

NE.NE.5 

5 

NE. 

SW. 

20 

5 

SW. 

SW. 

29 

5 

SE. 

SW. 

3 

4 

Producers  Oil  Co. 

Phillipson  No.  1 

500 

Producers  Oil  Co. 

Plog  No.  1 

519 

Producers  Oil  Co. 

Sam  Brown  No .  1 

499 

Producers  Oil  Co. 

Sam  Brown  No.  2 

497 

Donk  Bros.  Coal 

&  Coke 

481 

Donk  Bros.  Coal 

&  Coke 

483 

Producers  Oil  Co. 

E.  S.  Delaplane 

512 

Producers  Oil  Co. 

M.  J.  Wall 

571 

Donk  Bros.  Coal 

&  Coke 

550 

Donk  Bros.  Coal 

&  Coke 

539 

Donk  Bros.  Coal  & 

Coke,  J.  V.  Paine 

511 

Producers  Oil  Co. 

Johnson  No.  1 

499 

Ohio  Oil  Co. 

Kiedheimer  No.  1 

548 

D.  T.  Finley 

Phillip  Gloss  No.  1 

527 

Feabody  Coal  Co. 

Donnell 

558 

Sullivan  Machinery 

Co. 

493 

Sullivan  Machinery 

Co. 

523 

D.  M.  Bissonette 

490 

390 

110 

396 

123 

390 

109 

370 

127 

383 

98 

387 

96 

380 

132 

435 

136 

399 

151 

304 

235 

386 

125 

370 

129 

325 

223 

380 

147 

471 

87 

402 

91 

437 

91 

380 

110 

PROPER  TESTING   FOR  OIL  STRUCTURES   IN    ILLINOIS 


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Pig.  7.  Structure  map  and  generalized  columnar  section  of  area  near  Stubblefield  in  Bond  County. 

The  key  horizon  which  is  best  suited  for  use  in  Bond  County  is  a 
coal  which  will  be  found  at  a  depth  ranging  from  375  to  400  feet.  Logs 
of  these  te9ts  should  be  carefully  kept  for  the  entire  depth  of  the  well, 
because  correlation  is  difficult  in  this  area  and  is  likely  to  be  faulty  with 
incomplete  records. 

Several  deep  wells  have  been  drilled  both  near  Old  Ripley  and  north- 
west of  Pocahontas.  None  of  them  appears  to  have  been  located  on  the 
most  favorable  part  of  the  structure,  although  some  of  them  are  reported 
to  have  had  showings  of  oil. 

Although  it  is  to  be  expected  that  8  possible  producing  horizons 
will  be   found  in  the  Bond  County  area,  some  of  them  may  be  too  deep 


18  PROPER  TESTING  FOR  OIL  STRUCTURES   IX    ILLINOIS 

for  consideration  at  the  present  time.  In  the  Sam  Brown  well  No.  2  in  the 
SE.  yA  NE.  34  NW.  yA  sec.  9,  T.  5  N.,  R.  1  \Y.,  sands  were  found  at  the 
following  depths:  645  to  730,  750  to  760,  830  to  905,  1990  to  2003,  and 
2025  to  2034  feet.9  The  interpretation  of  this  log  is  that  the  formations 
from  1870  to  ]!)!)()  feet  are  basal  Mississippian  and  possibly  Devonian,  and 
that  the  sand  at  1990  is  Devonian  or  Silurian.  According  to  this  corre- 
lation, the  basal  Silurian  and  the  Trenton  have  not  been  drilled  in  this 
vicinity.  These  relations  are  shown  in  the  columnar  section  in  figure  7. 
In  the  area  recommended  for  testing,  these  same  sands  should  be 
found,  but  at  lesser  depths  because  of  the  higher  structure.  If  favorable 
structural  conditions  obtain,  it  is  probable  that  oil  will  be  found.  A  deep 
test   should   reach   the   Trenton   at    about   2500    feet. 

MONTGOMERY    COUNTY 
NOKOJIIS   AND  OHLMAN   DOMES 

As  a  result  of  an  investigation  of  coal  data  from  Montgomery  County, 
two  anticlinal  folds  have  been  mapped  in  the  vicinity  of  Nokomis  and 
Ohlman  (fig.  8).  According  to  the  information  available,  the  larger  of 
these  folds  is  near  Ohlman.  Further  tests  are  needed  to  give  more  de- 
tailed information  about  the  structure  before  a  deep  test. is  drilled  for  oil. 

In  order  to  determine  the  most  favorable  location  for  a  test  on  the 
dome  near  Ohlman,  it  will  probably  be  necessary  to  drill  about  five  struc- 
ture tests  to  the  coal  at  about  650  feet,  although  there  is  some  possibility 
that  the  limestone  found  at  shallower  depths  might  prove  to  be  a  satisfac- 
tory key  bed.  The  tests  should  be  located  on  the  north,  northeast,  east, 
southeast,  and  west  borders  of  the  shaded  area  in  figure  8. 

A  smaller  number  of  tests  would  determine  the  conditions  in  the  dome 
near  Nokomis.  With  the  data  now  available,  probably  three  tests  drilled 
on  the  north,  northwest,  and  west  sides  of  the  shaded  area  would  definitely 
outline  the  dome.  Although  the  doming  here  does  not  appear  to  cover 
as  large  an  area  as  that  near  Nokomis,  the  fact  that  a  smaller  amount  of 
preliminary  testing  is  required,  and  that  the  folding  seems  to  be  somewhat 
steeper,  suggests  that  the  Nokomis  dome  should  be  tested  before  the  Ohlman 
dome. 

There  is  probably  .no  chance  to  get  production  at  depths  less  than  700 
feet  on  either  dome,  as  many  wells  have  already  been  drilled  through  the 
strata  to  that  depth  without  getting  a  trace  of  oil.  The  Pennsylvania!! 
strata  will  probably  be  found  to  continue  to  a  depth  of  about  1250  feet. 
In  case  a  favorable  structure  is  found,  a  test  should  be  carried  to  a  depth 
of  about  1600  feet  in  order  to  test  the  Chester  of  the  upper  Mississippian. 
The  possible  oil  sands  are  shown  in  the  columnar  section   (fig.  8). 


•  Mylius,   L.   A.,   Revised   correlations,   Oil   and   gas    in   Bond,    Macoupin   and   Mont- 
gomery counties  by  R.  S.  Blatchley:   111.   State  Geol.   Survey  Bull.   28,   p.   18,  Oct.   1923. 


PROPER  TESTING   FOR  OIL  STRUCTURES   IN    ILLINOIS 


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20  PROPER  TESTING   FOR  OIL  STRUCTURES    1  \    ILLINOIS 

At  the  present  time  the  Ohlman  Dome  Oil  and  Gas  Company  of  No- 
komis  is  drilling  a  well  four  miles  north  of  Nokomis  which  should  give 
some  additional  information  on  the  stratigraphy  and  structure  of  the  region. 

Favorable  Areas  i.\  Southern  Illinois 

In  the  present  report  only  one  locality  in  the  southern  part  of  the  State 
is  considered.  After  the  completion  of  certain  detailed  work,  now  planned 
or  under  way,  other  areas  in  this  general  part  of  the  State  will  he  described. 

ST.    CLAIR    AND    WASHINGTON    COUNTIES 
THE    DARMSTADT    AREA 

The  Darmstadt  area  is  located  in  southeastern  St.  Clair  and  south- 
western Washington  counties.  It  has  been  described  previously,10  but  a 
new  map  was  made  for  the  present  paper  with  a  contour  interval  of  2o  in- 
stead of  50  feet.  A  greater  amount  of  detailed  structural  information  can 
he  shown  as  a  result  of  this  change. 

Xear  Darmstadt  there  is  an  area  which  should  be  investigated  further. 
Data  on  the  elevation  of  coal  beds  found  in  the  neighborhood  have  been 
interpreted  as  indicating  the  presence  of  a  plunging  anticline  and  the  area 
worthy  of  further  consideration  is  shaded  in  figure  !».  Test  wells  should 
be  drilled  along  the  middle  part  of  the  shaded  area  to  determine  whether 
the  anticline  plunges  continuously,  or  is  separated  into  local  domes  by  alter- 
nations of  steep  plunges  and  reverse  dips.  If  such  domes  are  found  along 
this  anticline,  deep  tests  should  be  drilled  to  test  the  oil  possibilities. 

Structure  tests  should  be  drilled  to  the  coal  at  depths  varying  from 
L50  to  200  feet.  Probably  :'>  or  4  such  tests  would  give  the  information 
needed  to  decide  the  advisability  of  putting  down  a  deep  test. 

The  Darmstadt  area  is  of  particular  interest  because  beds  within  easy 
reach  of  the  drill  are  known  to  contain  at  least  small  amounts  of  oil  nearby. 
In  the  vicinity  of  Sparta,  and  about  15  miles  south  of  Darmstadt,  several 
nice  wells  were  found  in  the  Chester  beds.  Six  miles  south  of  Darmstadt, 
near  Marissa,  two  of  the  deep  wells  reported  showings  of  oil  or  gas.  As 
Marissa  is  on  the  same  general  fold  as  that  at  Darmstadt,  and  as  shows  of 
oil  were  found  on  parts  of  the  structure  which  do  not  appear  to  be  particu- 
larly favorable,  the  chances  of  finding  oil  on  any  dome  which  might  be  found 
in  the  area  are  considered  good. 

At  least  four  sand  horizons  lie  within  easy  reach  of  the  drill  in  the 
vicinity  of  Darmstadt.  Xear  .Marissa.  they  have  been  reported  at  the  fol- 
lowing depths:  660  to  670,  685  to  697,  :;:  to  786,  789  to  son.  and  822  to 
842  feet.     Sands  will  probably  be  found  at  these  same  horizons  in  the  Darm- 


'"  Shaw.     E.     W.,     r.     S.     Geol.     Survej     Geol.     Atlas.     New     Athens-Okawville     folio 
(No.    213),    1921. 


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PROPER  TESTING  FOR  OIL  STRUCTURES    IX    [LLINOIS 

stadt  area,  [f  favorable  structural  conditions  arc  found,  an  oil  test  should 
be  drilled  to  MOO  feet  or  more  to  lest  the  upper  part  of  the  Mississippian  at 
least.  The  character  of  the  rocks  underlying  the  area  is  shown  in  the  col- 
umnar section,  figure  9. 

GENERAL  SUMMARY 

Indiscriminate  deep  drilling  in  advance  of  determination  of  structure 
is,  in  most  cases,  much  more  expensive  and  much  less  conclusive  than  the 
structure  drilling  program  outlined.  Therefore,  a  systematic  program  of 
determining  structure  in  advance  of  deep  drilling  has  been  suggested,  and 
certain  areas  in  which  such  drilling  can  well  be  undertaken  have  been  de- 
scribed. It  is  desirable  that  Illinois  operators  generally  will  recognize  the 
value  of  test  drilling,  and  will  use  it.  In  view  of  the  fact  that  one  half  of 
the  dry  holes  drilled  in  Illinois  during  1924  were  drilled  on  locations  which 
were  obviously  unpromising  from  a  geological  point  of  view,  operators  will 
probably  be  able  to  reduce  the  percentage  of  failures  by  locating  their  tests 
on  favorable  structures.  If  proper  testing  is  carried  out,  it  is  believed 
that  one  or  more  new  oil  pools  will  be  discovered,  and  that  new  drilling  will 
show  more  profit  than  in  the  past  year. 

Additional  help  can  be  obtained  from  the  State  Geological  Survey  in 
the  matter  of  identification  of  key  beds  and  deeper  beds  which  might  con- 
tain oil.  This  service  can  be  most  useful  to  the  operator  if  cutting  samples 
arc  carefully  kept,  and  sent  to  the  Survey.  Where  possible,  the  Survey 
will  also  provide  assistance  in  determining  the  elevation  of  structure  tests. 
As  valuable  information  not  included  in  the  present  report  can  be  obtained, 
operators  are  advised  to  address  any  inquiries  they  may  have  to  the  Illinois 
State  Geological  Survey.  Urbana,  Illinois. 


IUVS" 
LIBRARY  BINDERS 
507  &  Goodwin 
Urbona,IlL 


